The general term “paper” is understood as meaning about 3000 different types and articles whose nature and fields of use in some cases differ considerably. For the production of paper, a number of additives are required, of which fillers (i.e. chalk or kaolin) and binders (e.g. starch) are among the most important. For the area of tissue and hygiene papers which are brought into relatively close contact with human skin, there is a particular need for a pleasant soft feel which is usually imparted to the paper by a careful choice of the fibers and in particular a high proportion of fresh groundwood or cellulose. With regard to the cost-efficiency of papermaking and from an ecological point of view, however, it is desirable also to use as high proportions as possible of low-quality waste paper. However, the result of this is that the soft feel of the paper is adversely affected to a significant extent, which is found to be troublesome by the users and, in particular with frequent use, can also lead to skin irritations.
In the past, there has therefore been no lack of attempts to modify tissue papers by impregnation, coating or other surface treatment so that a pleasant soft feel results. Special lotions and emulsions which firstly can be easily be applied to the paper and secondly do not adversely affect the paper structure must be developed for this purpose. In order to improve the soft feel, frequently nonionic surfactants or a combination of nonionic and anionic surfactants are used. Polysiloxanes and cationic polymers are also used for this purpose.
International patent application WO 95/35411 relates to tissue papers which are coated with finishing compositions which contain from 20 to 80% by weight of an anhydrous emollient (mineral oils, fatty acid esters, fatty alcohol ethoxylates, fatty acid ethoxylates, fatty alcohols and mixtures thereof), from 5 to 95% by weight of an emollient-immobilizing agent (fatty alcohols, fatty acids or fatty alcohol ethoxylates having in each case 12 to 22 carbon atoms in the fat radical) and from 1 to 50% by weight of surfactants having an HLB value of, preferably, from 4 to 20. The working examples mentioned in the document contain without exception petrolatum as the emollient. International patent application WO 95/35412 discloses similar tissue papers, anhydrous mixtures of (a) mineral oils, (b) fatty alcohols or fatty acids and (c) fatty alcohol ethoxylates being used as softeners. International patent application WO 95/16824 relates to finishing compositions for tissue papers which contain mineral oil, fatty alcohol ethoxylates and nonionic surfactants (sorbitan esters, glucamides). Furthermore, international patent application WO 97/30216 (Kaysersberg) describes liquid finishing compositions for paper tissues based on long-chain, saturated fatty alcohols and wax esters having altogether at least 24 carbon atoms, which finishing compositions contain a very high proportion of water. From the point of view of use, soft feel, processing behavior and sensory properties of the treated papers are still worthy of improvement. DE 10102500 A1 relates to lotions which contain (a) polyol poly-12-hydroxystearates, (b) oily substances selected from the group consisting of the glycerides, hydrocarbons, silicone oils, dialkyl ethers and dialkyl carbonates, or any desired mixtures thereof, and (c) 5-25% by weight of water and are suitable, as described in EP 1 225 276 A1, also for the coating of papers. These emulsions and lotions are still worthy of improvement with respect to the stability. In particular, it is frequently not possible to incorporate plant extracts without a color change, which has a disadvantageous effect on the whiteness of the paper to be coated.
It was the object of the invention to provide emulsions having improved stability and with the aid of which dry commodity papers, in particular tissue papers, but also reinforced tissue can be coated without significantly reducing the whiteness of the paper. The emulsions should have excellent care properties, and should resemble classical skin care formulations with regard to sensory properties. A further aspect of the object is to provide preparations which are also compatible with tissue papers with a high proportion of waste paper. At the same time, only readily biodegradable auxiliaries should be used and the preparations should penetrate easily into the tissue, be homogeneously distributed, have a relatively low water content and, in highly concentrated form, nevertheless have such a low viscosity that they can be readily processed.